Simple question, but I couldn’t find the answer in the yellow paper.
Is it reset to 0 or is it kept at the latest value before destruction ?
Ethereum addresses with a codesize > 0 should always have a nonce of zero, as the address it sits at is created deterministically from the transaction that adds the code (creates the contract), and not from a private key. Thus the contract itself can never make transactions and its nonce can never be increased.
Nonces only increase with addresses that can make (sign) transactions